The technologies for the removal of coal technogenic deposits in the form of highly concentrated hydro mixtures

Abstract

An analysis of the existing beneficiation coal waste storage facilities was carried out and ecologically friendly ways of lowering the water level and removing man-made deposits in the form of highly concentrated aqueous mixtures were carried out. The methodology for calculating the parameters and regimes of transportation for the man-made deposits waste with a high content of pollutants in the form of highly concentrated aqueous mixtures was developed. Models of the processes that occur during the extraction and transportation of man-made deposits in the form of highly concentrated aqueous mixtures were developed taking into account promising technologies. In case of an aqueous mixture with the significant initial tangential stress value, the transport of a highly concentrated aqueous mixture model along a vertical pipeline using a screw conveyor was developed. In this case, it is assumed that the aquous mixture will be lifted up at a height that ensures a nonpressure flow to the levee, where the aqueous mixture will be liquefied and its further transportation by pressure transport, vehicles or railway transport. The model of the process of the pressure flow of a highly concentrated aqueous mixture through the horizontal pipeline, depending on the transportation distance, provides for the use of centrifugal type pumps or piston pumps. Depending on the relative radius value for the undisturbed core of flow, the model takes into account the three most probable flow modes of highly concentrated aqueous mixtures through a circular cross-section pipeline and allows to perform both design and verification calculations. When the gravity force is used to transport a highly concentrated aqueous mixture to the shore, a mathematical model of nonpressure flow process of an aqueous mixture along an inclined channel with a rectangular cross-section was developed. This model takes into account the channel inclination angle, its width and the rheological parameters of the aqueous mixture and allows to calculate the geometric parameters of the channel, which are necessary to ensure the predefined transportation distance with the required flow rate. The results of the study could be applied for coal beneficiation waste storage facilities when they are out of maintenance, which will contribute to the elimination of technogenic impact on the environment, while for waste storage facilities that operate, appliance of the proposed technologies is a way of their size containing. Keywords: coal beneficiation waste storage, man-made deposits, highly concentrated aqueous mixtures.